ForeverPharm,
Personally, I don't think that volunteering in the hospital, just for volunteering's sake is going to get you much pharmacy expericene, unless of course, you actually are volunteering in the hospital's pharmacy.
Have you tried going to the pharmacy and asking if you could volunteer there? I have had success with finding 2 hospital pharmacies that allowed me to volunteer. Just tell them what you are wanting (ie. you are a prepharm student looking to gain some experience) I told the pharmacy director where I got my volunteer positions that I wanted to make sure that this is definitely the path that I want to take and any exposure that I can get (whether it is hands-on or through osmosis by just being in the pharmacy environment) will be very beneficial to me.
Shadowing in a community pharmacy will (in my opinion) be better than being the ER's waiter! But maybe try going to the pharmacy at the hospital and asking them if you could help them out with some volunteer hours.
Good luck!